Process for protecting a substrate with an arylsulfonamide derivative intumescent agent

ABSTRACT

INTUMESCENT COMPOSITIONS OF THE INVENTION COMPRISE CERTAIN ARYLSULFONAMIDOTHIAZOLES, ISOTHIAZOLES, OXAZOLES, AND ISOXAZOLES, SUCH AS 2-SULFANILAMIDOTHIAZOLE, 5-SULFANILAMIDOISTHIAZOLE, 2-SULFANILAMIDOOXAZOLE, 5-SULFANILAMIDOISOXAZOLE, AND DERIVATIVES THEREOF. THE INTUMESCENT AGENTS MAY BE EMPLOYED IN CONJUCTION WITH ADDITIVES CONVENTIONALLY USED IN INTUMESCENT COMPOSITIONS. FOR USE IN PROTECTING SUBSTRATES FROM HEAT AND FIRE, THE INTUMESCENT COMPOSITIONS MAY BE APPLIED TO THE SUBSTRATES IN ANY SUITABLE MANNER, EACH AS BY ELECTRODEPOSITION, SPRAYING ONTO AN ADHESIVE SUBSTRATE, OR APPLICATION OF A COATING COMPOSITION COMPRISING THE INTUMESCENT AGENT.

toe-mat United S1 l: Elfil?) l 3,783,015 PROCESS FOR PROTEC G ASUBSTRATE WITH AN ARYLSULFONAMIDE DERIVATIVE INTU- MESCENT AGENT ShirleyH. Roth, Highland Park, N.J., assignor to Cities Service Company, NewYork, N.Y. No Drawing. Filed Feb. 22, 1972, Ser. No. 228,382 Int. Cl.C09d 5/18; C09k 3/28 U.S. Cl. 117-136 8 Claims ABSTRACT OF THEDISCLOSURE BACKGROUND OF THE INVENTION Field of the invention Thisinvention relates to intumescent compositions and more particularlyrelates to such compositions containing a one-component intumescentagent.

Description of the prior art It is known that a substrate may beprotected from heat and fire by the application of an intumescentcomposition. Intumescent compositions of the prior art usually containan intumescent agent having at least three components; Le, a carbonific,a spumific, and a catalyst; and they are typically characterized by thedisadvantages of high cost, low spreading rate, relatively poorefiiciency, poor water resistance, and poor Weatherability.

As disclosed in US. Pat. 3,535,130, it has already been discovered thata one-component intumescent agent has advantages over multicomponentintumescent agents. However, the intumescent agents of the patent havepoor adherence to substrates and have an undesirable degree of moisturesensitivity.

SUMMARY OF THE INVENTION An object of this invention is to provide anovel class of one-component intumescent agents.

Another object is to provide such intumescent agents having goodefiiciency and a low level of moisture sensitivity.

These and other objects are attained by using as intumescent agentscompounds corresponding to the formula:

wherein Ar is a divalent aromatic residue, R is hydrogen, hydrocarbon,halohydrocarbon, or acyl, and R" is a thiazolyl, substituted thiazolyl,isothiazolyl, substituted isothiazolyl, oxazolyl, substituted oxazolyl,isoxazolyl, or

. substituted isoxazolyl radical.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The intumescent agents of theinvention may be any compounds corresponding to the above formula.However, they are preferably compounds wherein Ar is a 3,783,015 entedJan. 1, 1974 divalent aromatic residue derived from benzene ornaphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy,carboxyl, amino, amido, or nitro derivative thereof. When the aromaticring bears organic substituents, it is usually preferred that thesesubstituents contain 1-5 carbon atoms. When there are halo substituents,it is usually preferred that they be chloro or bromo. It is alsopreferred that the aromatic ring have at least one free reactiveposition.

As indicated above, R of the formula may be hydrogen or a hydrocarbon,halohydrocarbon, or acyl radical, e.g., an alkyl, chloroalkyl, orbromoalkyl radical containing 1- 5 carbon atoms, a phenyl, chlorophenyl,or bromophenyl radical, or an aliphatic or aromatic acyl radical.

R is frequently a thiazolyl, isothiazolyl, oxazolyl, or isoxazolylradical, but it may bear one or more substituents if desired. Thesubstituted thiazolyl, isothiazolyl, oxazolyl, and isoxazolyl radicalsmost commonly found in these compounds are the hydro, chloro, bromo,oxy, keto, carboxy, hydroxy, amino, amido, sulfonamido, nitro, C Calkyl, phenyl, and benzo derivatives, but compounds containing othersubstituted thiazolyl, isothiazolyl, oxazolyl, or isoxazolyl radicalsare also utilizable. When R" is such a substituted radical, the nitrogenof the sulfonamide group may be attached directly to the thiazole,isothiazole, oxazole, or isoxazole ring, or it may be attached to thering through the substituent.

Exemplary of the intumescent agents of the invention are2-sulfanilamidothiazole,

3-sulfanilamidoisothiazole,

2-sulfanilamido oxazole,

3-su1fanilamidoisoX-azole,

2- (4-amino-3-chlorobenzenesulfonamido )thiazole,

2- (2-amino-4-bromob enzenesulfonamido thiazole,

2- (4-amino-2-ethylbenzenesulfonamido) thiazole,

4- 3 -amino-4-chloromethylb enzene sulfonamido thiazole,

5- (4-amino-Z-butoxybenzenesulfonamido thiazole,

2- (4-amino-3 -chloromethoxybenzenesulf'onamido) thiazole,

2- (4-amino-3-hydroxybenzenesulfonamido) thiazole,

2- (4-amino-3-carboxybenzenesulfonamido) thiazole,

2- (3 ,4-diaminob enzenesulfonamido) thiazole,

2- (4-amino-2- acetamidobenzenesulfonamido thiazole,

2- (Z-amino-4-nitrobenzenesulfonamido) thiazole,

2- 4-methylaminobenzenesulfonamido thiazole,

2- 4-chloroethylaminobenzenesulfonamido thiazole,

2- 4-bromomethylaminobenzenesulfon amido thiazole,

2- 4-phenylaminobenzenesulfonamido thiazole,

2- [4- (p-chlorophenylamino benzenesulfonamido] thiazole,

2- [4- (p-bromophenylamino) benzenesulfonamido] thiazole,

2- (p-acetamidobenzenesulfonamido thiazole,

2- (p-benzamidobenzenesulfonamido) thiazole,

3-methy1-2-sulfanilamidothiazolidine,

4-chloro-2-sulfanilamidothiazole,

4-bromo-2-sulfanilamidothiazole,

4-ethoxy-Z-sulfanilamidothiazole,

2-sulfanilamido-4-thiazolone,

5-methylketo-2-sulfanilamidothiazole,

4- carboxy-2-sulfanilamidothiazole,

4-hydroxy-Z-sulfanilamidothiazole,

5-hydroxyethyl-4-methyl-Z-sulfanilamidothiazole,

S-amino-2-sulfanilamidobenzothiazole,

4-(4-aminophenyl) -2-sulfanilamidothiazole,

S-methylamido-2-sulfanilamidobenzothiazole,

6-sulfonamido-2-sulfanilamidobenzothiazole,

6-nitro-2-sulfanilamidobenzothiazole,

4-methyl-2-sulfanilamidothiazole,

Z-methyl-S-sulfanilamidothiazole,

4,5-dimethyl-2-sulfanilamidothiazole, S-methyl-2-sulfanilamidothiazole,4-phenyl-Z-sulfanilamidothiazole, 2-sulfanilamidobenzothiazole,

the corresponding naphthalene compounds, the corresponding derivativesof isothiazole, oxazole, and isoxazole, etc. When not readily available,these compounds may be prepared by known techniques.

For use in protecting a substrate from heat and fire, the intumescentagents of the invention may be applied in any suitable manner, e.g.,electrodeposition, spraying of pow dered intumescent agent onto anadhesive substrate, etc. However, it is usually preferred to compoundthe intumescent agent with a binder, e.g., nitrocellulose, andoptionally also with one or more of the other ingredients conventionallyused in intumescent compositions, e.g., stabilizers, dispersing agents,pigments, driers, biocides, anti-foamers, thickeners, protectivecolloids, fillers, blowing agents, etc.; disperse the composition in asuitable liquid medium, e.g., water or a solvent or solvent mixture; andapply the coating composition thus formed to the substrate to beprotected. As is the case with conventional intumescent coatingcompositions, it is frequently convenient to apply these coatingcompositions in the form of a paint having a solids content of about-70% by weight and an intumescent agent/binder weight ratio of about0.075-l4/1 to deposit a coating having a dry thickness of about0.001-0.75 inch.

The intumescent agents of the invention are efficient, have low moisturesensitivity, and intumesce to form foams having good volume, cellstructure, and adherence to substrates, such as wood, metal, andplastics. They are also useful as flame retardants in normally flammablecompositions.

The following example is given to illustrate the invention and is notintended as a limitation thereof.

Example I Place one gram of 2-sulfanilamidothiazole in an aluminum panand flame it with a propane torch. The compound intumesces to form anexcellent volume of foam having a good cell structure.

Similar results are also observed when 2-sulfanilamido-4-methylthiazole, S-sulfanilamido 3 methylisothiazole, 2-sulfanilamido4,5 dimethyloxazole, 3-sulfanilamido- S-methylisoxazole, and the otherintumescent agents mentioned in the specification are substituted forthe intumescent agents of the example.

It is obvious that many variations may be made in the products andprocesses set forth above without departing from the spirit and scope ofthis invention.

What is claimed is:

ll. A process for protecting a substrate from heat and fire whichcomprises applying thereto an intumescent composition comprising as theintumescent agent a compound corresponding to the formula:

wherein Ar is a divalent aromatic residue, R is hydrogen, hydrocarbon,halohydrocarbon, or acyl, and R" is a thiazolyl, substituted thiazolyl,isothiazolyl, substituted isothiazolyl, oxazolyl, substituted oxazolyl,isoxazolyl, or substituted isoxazolyl radical.

2. The process of claim 1 wherein Ar is a divalent aromatic residuederived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy,haloalkoxy, halo, hydroxy, carboxy, amino, amid-o, or nitro derivativethereof.

3. The process of claim 1 wherein R" is a thiazolyl, isothiazolyl,oxazolyl, or isoxazolyl radical or a hydro, halo, oxy, keto, carb'oxy,hydroxy, amino, amido, sulfonamido, nitro, alkyl, phenyl, or benzoderivative thereof.

4. The process of claim ll wherein the intumescent agent is2-sulfanilamidothiazole.

5. The process of claim 1 wherein the intumescent agent is2-sulfanilarnido-4-methylthiazole.

6. The process of claim 1 wherein the intumescent agent is5-sulfanilamido-3-methylisothiazole.

7. The process of claim 1 wherein the intumescent agent is2-sulfanilamido-4,5-dimethyloxazole.

8. The process of claim 1 wherein the intumescent agent is3-sulfanilamindo-S-methylisoxazole.

References Cited UNITED STATES PATENTS 3,535,130 10/1970 Webb 117-136X3,663,464- 5/1972 Sawko ll7-l36X 3,707,554 12/1972 Hardy 117-136X OTHERREFERENCES Northey, Sulfonamides, pp. 33, 34, 85, 86, 88-90 (1948).

WILLIAM D. MARTIN, Primary Examiner H. J. GWINNELL, Assistant ExaminerU.S. Cl. X.R. 106-15 FP

